Barbara Brotman wrote this “Arbor Day love song,” in the April 25th edition of The Chicago Tribune. In the column, Brotman was reporting on the Morton Arboretum’s plan to have staffers tag more than 500 trees in downtown Chicago to show their environmental benefits over 15 years in dollar values. The total for the 500-plus trees tagged was $620,005.

These dollar figures were factored using the National Tree Benefit Calculator, a computer model based on 25 years of research by the U.S. Forest Service and partner companies, including The Davey Tree Expert Co. Scott Maco, a Davey expert and research urban forester, discussed the calculator and tree benefits in the article.

Then Brotman goes on to ask how much a tree is worth to the reader. She gives a tree shaped just right for a rope swing a $500 value and any trees that shade a hiking path a $1,000 value. She gives the highest value – $10,000 – to the feeling of lying in the grass beneath a big tree in the summer.

How much is a tree worth to you? Find out its real value using the National Tree Benefit Calculator. But if you have a special value you’d like to put on your favorite tree, share your story with us here.

Learn more about valuing trees below or read the story in The Chicago Tribune. – Nicole Wisniewski

Arbor Day project to sprout in Chicago

Putting value tags on trees to showcase environmental benefits

Barbara Brotman April 25, 2011

How much is a tree worth?

At this particular moment, when all around us trees are on the verge of bursting into glorious leaf, a fortune.

But come Friday, Arbor Day, we'll be seeing price tags.

On Thursday, staffers and volunteers from the Morton Arboretum will descend on downtown Chicago and place tags on more than 400 trees showing the dollar value of the environmental benefits supplied by each one over a span of 15 years. Tags also will be attached to 100 trees at the arboretum in Lisle and the Yorktown Center in Lombard.

So how much is a tree worth, environmentally? A ginkgo on Randolph Street, for example: More than $2,600 in environmental savings over the next 15 years. The total for the 500 or so trees being tagged: $620,005.

The dollar figures come courtesy of the National Tree Benefit Calculator, a computer model based on 25 years of research by the U.S. Forest Service and its partners, said Scott Maco, manager of ecosystems services at the Davey Tree Expert Co., one of those partners.

The model used different methods to come up with the dollar amounts. To quantify the value of a tree's ability to divert carbon from the atmosphere, for example, the calculator estimates how much carbon a particular species and size of tree stores in its trunk and branches, said Maco, who helped create the calculator. Then it assigns a figure based on the current trading value on open markets of carbon offset credits.

For another factor, trees' absorption of pollutants, he said, the calculator bases the value on a combination of what it would cost to control the pollution and the costs of damaging health effects.

The Morton Arboretum used the National Tree Benefits Calculator to make the value tags for the 500 trees. The tagging project, which the arboretum is conducting in partnership with the city, is intended to encourage people walking around downtown to pause, look at the tags, and think anew about the trees bearing them.

"We just want to draw people's attention to the great tree assets of Chicago and help them understand that they are contributing great environmental values," said Gerard Donnelly, president and chief executive officer of the Morton Arboretum, who will join in the tagging.

You can join in the science fun. The arboretum has posted a link to the National Tree Benefit Calculator on its website (www.mortonarb.org/arborday). By typing in a few facts, I found out that the silver maple in my backyard provides annual benefits of $213.

"We're putting dollar amounts on this, but I don't know that dollar equivalents are really the best measure," Donnelly said. "How valuable is it to … cool the places we live or enhance the natural elements of our towns and cities? You could say priceless."

So for your own personal Arbor Day observance, you might consider a different question. How much is a tree worth — to you?

Go ahead, make a list. Mine would look partly like this:

That charming set of small trees along the curving path that opens to the lakefront on the Museum Campus: $200.

The bur oaks majestically punctuating in the open meadows of the Spring Lake Nature Preserve near Barrington Hills: $500.

The massive, gnarly oak tree in my neighbors' yard that seems to fill the whole sky with greenery and birdsong: $1,000.

The solitary, perfectly formed maple in my local park that every fall turns a spectacular fiery red: $500.

That osage orange tree near my house that drops those green brain-shaped fruit that I collect and display every autumn: $800.

Trees shaped just right for a rope swing: $500.

The sources of maple syrup: $1,000.

That delicious shade of spring green we are about to see on all the leaves: $2,500.

The maple in our backyard that grows so close to my daughter's bedroom window it feels like a tree house: $2,500

The formally planted rows of trees in the older sections of Grant Park: $2,000.

The tangles of trees of the Paul Douglas Nature Sanctuary (Wooded Island) in Jackson Park: $1,250.

Any tree that shades a hiking trail in summer: $1,000.

The trees of Columbus Park: $5,000.

The feeling of lying in the grass beneath a big tree in summer: $10,000.

Assign your own values to the trees you love. And read the official ones; you'll see tags Friday in Chicago on trees around City Hall, Millennium Park, State Street, and Adams and Washington streets.

It will all add up to a fine Arbor Day love song. With respect to the scientists and apologies to Joyce Kilmer, I would also add this: